Today, when an emergency call is placed from a landline telephone, the address of the landline telephone is automatically displayed at the emergency center or at the Public Safety Answering Point (hereinafter “PSAP”) operator's screen. However, when such a call is placed from a cellular telephone, the caller's location is not shown on the operator's screen, and the caller must identify his/her location to the operator, otherwise, the location at which the call was initiated is not passed along to the operator. In other cases, even though the caller is able to communicate with the emergency center operator, still, he/she may be unable to provide the operator with his/her current location. Accordingly, all cell phone users are at a disadvantage when contacting emergency operators as compared with those who place such a call from a landline telephone. This is not a problem to be taken lightly particularly with the ever growing number of people using their mobile telephones as their first and foremost means of communication.
In a NENA (National Emergency Number Association) i3 Technical Requirements Document (TRD), NENA 08-751, Issue 1, Sep. 28, 2006, the routing of calls to the correct PSAP is based upon the location of the caller known at the time of the call. The main reason being that many people when calling the emergency line for any of a number of reasons do not provide (or unable to provide) to the PSAP operator their exact location, a fact that adds an undue delay while making an attempt to trace the caller.
The US Federal Communications Commission (FCC) requires that cell phone carriers must automatically provide the location of 911 calls made from a cell phone to PSAPs within certain accuracy parameters (specifically, within 50 meters 67% of the time and within 100 meters 95% of the time). The FCC has raised additional requirements with respect to providing precise location data for a 911 call made from inside a building, structure or facility as failure to provide precise location data of the caller may place him/her life in jeopardy. For example, upon responding to a 911 call based upon GPS location data, one might still have to search dozens or even hundreds of apartments or offices before being able to locate the 911 caller.
In order to find the location of a mobile device caller who placed an emergency 911 call, the PSAP operator retrieves data from the mobile network, and from the retrieved data one may be informed which base station serves that mobile device. However, since a base station coverage in urban areas extends to a radius of up to about 500 meters to 1 km away from the base station, it might still be difficult and sometimes even impossible to locate the caller within the accuracy required. In order to overcome this problem several attempts have been made while using Global Positioning Signal (“GPS”) or Time Distance of Arrival (“TDOA”) between base stations to provide location data. Other proposed systems rely on the employment of triangulation methods to locate the device by comparing signal strength and/or angle-of-arrival information from multiple antennas.
However, all these solutions are able to provide only limited answer to the problem of providing accurate location data and particularly in urban areas, and do not solve the problem when the cell phones are used in establishments such as hotels, apartment and office buildings, factories, schools and the like.
Furthermore, even when an emergency call is made from a landline telephone in an office that is connected via a Private Branch eXchange (“PBX”), then typically, only the street address appears at the operator's screen. The operator would therefore only know the residential address from which the call was placed but not the exact apartment/office/room where it was made, unless the caller is able to speak with the responding operator and to provide the missing information.
Following are a number of examples of solutions that are known in the art.
US2002005804 discloses a system for determining the location of a mobile station in a cellular communications network. The solution disclosed, relies on a plurality of locator units fixedly positioned for tracking and measuring communications between a base station and a mobile station initiating an emergency communication. Each such locator unit comprises a receiving means for monitoring a control channel of the base station in order to detect and receive identifying information including a voice channel assigned for the particular mobile device initiating the emergency communication.
U.S. Pat. No. 7,260,186 describes an emergency 911 voice-over-IP (VoIP) solution. The 911 call is initiated from a mobile VoIP device and routed directly to the correct PSAP via dedicated trunks, together with correct location information and call-back number. VoIP gateways are implemented locally, accept VoIP packetized data inbound, and convert it into standard landline voice call. The call is then routed to an IP address at the VoIP gateway, which then egresses the call to a voice port at a selective router. The location of the VoIP is validated using HTTP based protocol by pushing location information to a VoIP location server, and comparing it against a geographic location database to confirm that a contained street address is valid.
U.S. 20070004379 describes a method for providing location data to a 911 operator of a cell phone caller who initiated a 911 call. When a cellular 911 call is made within proximity of a landline telephone or a stand-alone unit, an interaction takes place between the enabled cell phone and the landline telephone. Upon receiving and decoding the cellular transmission, the landline telephone or stand-alone unit transmits a 911 call which provides more precise location data to a 911 operator than if the 911 call was simply connected to the operator from the cell phone.
U.S. Pat. No. 7,315,735 discloses a location detection system for locating a mobile device placing an emergency 911 call within a facility having a distributed antenna system. The location detection system includes detection units located within the distributed antenna system where each detection unit monitors a dedicated emergency 911 channel for activity and alerts a monitor unit if activity is detected. The monitor unit determines the location of the antenna receiving the emergency 911 call based upon the identity of the detection unit.
Due to the difficulties associated with providing 911 operators with precise location data from cell phones and office phones in the circumstances described above, it is required to provide a system, device and method for providing more precise location data to an emergency center operator without requiring the caller to verbally communicate location data to the operator.
Notwithstanding the above, one other problem associated with placing a call to an emergency center from a mobile device, and particularly in crowded urban areas such as hotels, office towers and the like, is the availability of a communication path for the caller to place that call. When a caller wishes to place such an emergency call in such areas, he/she could very well find himself/herself in a situation where there is no available link to reach the cellular network for placing the call. This will be the typical case if the caller is for example in a hotel when a fire, terrorist attack and the like takes place. In any of these cases most of the people present at that location would try to use their cellular telephones, and consequently the base station servicing that area will be unable to cope with the congestion.
Therefore, there is a need for reliable method and means to allow identifying the location of a mobile device caller who places a call to the emergency service where the caller is located in a room of a multi-tenant complex such as an office building or hotel, and the like.